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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 1, January/February 2019
AFRICA
27
and behavioural risks.
31
Biological factors include chromosome
differences and sex hormones, which serve as a mechanism of
protection against hypertension in most young women until they
reach menopause.
32
In contrast to our study, Luz
et al.
33
reported the prevalence
of hypertension to be 54.6 and 71.3% in men and women,
respectively. The study focused more on older adults rather
than young adults. As women grow older, their oestrogen levels
decrease while the pituitary hormones increase, thus putting
older women at a greater risk of developing hypertension than
men.
34
In our study, the prevalence of central obesity was found
to be higher in women (35.4–69.6%) than in men (1.4–30.2%).
Barbosa
et al.
26
also found a higher prevalence of central obesity
in women (65.1%) than men (40.1%), as did Munaretti
et al.
35
(women 63.2%; men 18.7%). Women have a larger amount of
body fat compared to men.
36
In addition, lifestyle risks such
as excessive consumption of diets rich in refined fats, oil and
carbohydrates contribute to the elevation of central obesity.
37
Most studies are in agreement with our study as they have
also reported the incidence of general obesity to be higher in
women than in men.
38,39
Al-Hazzaa
et al
.
40
reported that general
obesity can be high in either men or women, taking into account
their behavioural risk factors such as smoking and alcohol
consumption.
We found that WC and overweight were significantly
associated with hypertension and can best be used to predict the
risk of hypertension in individuals who are obese. Sakurai
et al
.
25
also reported a strong association between WC and hypertension
among Asians aged 19 to 33 years. Furthermore, Zhu
et al
.
24
found that WC, overweight and hypertension were significantly
correlated in white Americans living in an urban setting.
However, our findings contradict those reported by Munaretti
et al
.
35
in which WHR was shown to be a significant predictor
of hypertension. The contradiction between the two studies is
probably because WHR is considered to have greater accuracy
because of the nature of the measurements required, compared
to WC and participants’ age categories. The study setting was
also different.
22
Individuals with high WC in our study were at a
greater risk of developing hypertension.
Although the current study found WC and overweight to be
the best predictors for hypertension, Hou
et al.
41
reported that the
prediction of individuals who are at a greater risk of developing
CVD, specifically hypertension, can be improved by combining
WC, WHR and BMI. These findings are consistent with
those published previously.
24,42
However, Hans
et al
.
43
reported
that the WC parameter has several advantages compared to
other parameters because of its ease of measurement and
interpretation in most clinical settings.
The present study did not include predisposing factors such
as diet, lifestyle and level of physical activity for central obesity.
Other important factors associated with hypertension, such as
medical history, family history, alcohol intake and smoking, were
not assessed. The study had a low sample size therefore its findings
cannot be representative of all young adults in South Africa.
Conclusion
The prevalence of hypertension was high in men compared
to women. Hypertension was significantly related to WC and
overweight (the sum of four skinfolds). It is vital to investigate
the relationship between lifestyle and biological risk factors for
cardiovascular disease over time.
The financial support received from University of Limpopo, South Africa,
and the National Research Foundation of South Africa, for the Ellisras
Longitudinal Study is gratefully acknowledged. Any opinions, findings and
conclusions or recommendations expressed in this report are those of the
authors and therefore the above funding sources do not accept any liability
in regard thereto. The authors are indebted to ELS administrators, Seleka
Simon, Makata William and Jan Mabote, for providing technical support in
the preparation of this manuscript.
References
1.
He H, Kimura S, Fujisawa Y, Tomohiro A, Kiyomoto K, Aki Y, Abe
Y. Dietary L-arginine supplementation normalizes regional blood flow
in Dahl-Iwai salt-sensitive rats.
Am J Hypertens
1997;
10
(S4): 89S–93S.
2.
Fuentes R, Ilmaniemi N, Laurikainen E, Tuomilehto J, Nissinen A.
Hypertension in developing economies: a review of population‐based
studies carried out from 1980 to 1998.
J Hypertens
2000;
18
(5): 521–529.
3.
Gersh BJ, Sliwa K, Mayosi BM, Yusuf S. Novel therapeutic concepts
the epidemic of cardiovascular disease in the developing world: global
implications.
Eur Heart J
2010;
31
(6): 642–648.
4.
Jung UJ, Choi MS. Obesity and its metabolic complications: the role of
adipokines and the relationship between obesity, inflammation, insulin
resistance, dyslipidemia and nonalcoholic fatty liver disease.
Int J Mol
Sci
2014;
15
(4): 6184–6223.
5.
Montani JP, Antic V, Yang Z, Dulloo A. Pathways from obesity to
hypertension: from the perspective of a vicious triangle.
Int J Obes
2002;
26
(S2): S28.
6.
Janssen I, Katzmarzyk PT, Ross R. Waist circumference and not body
mass index explains obesity-related health risk.
Am J Clin Nutr
2004;
79
(3): 379–384.
7.
Richard N. Obesity-related hypertension.
Ochsner J
2009;
9
(3): 133–136.
8.
Sanchez-Viveros S, Barquera S, Medina-Solis CE, Velazquez-Alva MC,
Valdez R. Association between diabetes mellitus and hypertension with
anthropometric indicators in older adults: results of the Mexican Health
Survey, 2000.
J Nutr Health Aging
2008;
12
(5): 327–333.
9.
Silva SM, Facchini LA, Tomasi E, Piccini R, Thume E, Silveira DS,
et
al
. Advice for salt, sugar and fat intake habits among adults: a national-
based study.
Rev Bras Epidemiol
2013;
16
: 995–1004.
10. Nafiu OO, Zepeda A, Curcio C, Prasad Y. Association of neck circum-
ference and obesity status with elevated blood pressure in children.
J
Hum Hypertens
2014;
28
(4): 263.
11. Idler EL, Benyamini Y. Self-rated health and mortality: a review of
twenty-seven community studies.
J Health Soc Behav
1997: 21–37.
12. Monyeki KD, Kemper HCG, Makgae PJ. Relationship between fat
patterns, physical fitness and blood pressure of rural South African
children: Ellisras Longitudinal Growth and Health Study.
J Hum
Hypertens
2008;
22
: 311–319; advance online publication, February 14,
2008; doi:10.1038 /jhh. 2008.3
13. Sidiropoulos E, Jeffery A, Mackay S, Gallocher R, Forgey H, Chips C.
South Africa Survey 1995/1996. Johannesburg: South African Institute
of Race and Relations 1996: 234–360.
14. Statistics South Africa. Cause of death in South Africa 1997–2001.
Advance Release of Records of Death. Pretoria: Statistics South Africa,
2002: 18–42.
15. Monyeki KD, Van Lenthe FJ, Steyn NP. Obesity: does it occur in
African children in a rural community in South Africa?.
Int J Epidemiol